Toán 12 Tìm số thực thỏa mãn

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hn3

[TEX](1-2i)^3=1^3-3.1.2i+3.1.(2i)^2-(2i)^3=1-6i-12+8i=-11+2i[/TEX]

[TEX]x(3+5i)+y(1-2i)^3=x(3+5i)+y(-11+2i)=(3x-11y)+(5x+2y)i[/TEX]

[TEX](3x-11y)+(5x+2y)i=7+32i[/TEX]

[TEX]\left{\begin{3x-11y=7}\\{5x+2y=32}[/TEX]

[TEX]\left{\begin{x=6}\\{y=1}[/TEX]

:)
 
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